Mitochondria are organelles in eukaryotic cells. They generate most of the cell's supply of adenosine triphosphate (ATP), which is used as an energy source. Thus, mitochondria are indispensable for energy production, for the survival of eukaryotic cells and for correct cellular function. In addition to supplying energy, mitochondria are involved in a number of other processes such as cell signalling, cellular differentiation, cell death as well as the control of the cell cycle and cell growth. In particular, mitochondria are crucial regulators of cell apoptosis and they also play a major role in multiple forms of non-apoptotic cell death such as necrosis.
In recent years many papers have been published describing mitochondrial contributions to a variety of diseases. Some diseases may be caused by mutations or deletions in the mitochondrial genome, while others may be caused by impairment of the mitochondrial respiratory system or other kind of damage of the mitochondrial function. At present there is no available treatment that can cure mitochondrial diseases.
In view of the recognized importance of maintaining or restoring a normal mitochondrial function or of enhancing the cell's energy production (ATP), there is a need to develop compounds, which have these properties.
Succinate compounds have been prepared as prodrugs of other active agents, for example WO0208345 describes succinic acid bis(2,2-dimethylpropionyloxymethyl) ester, succinic acid dibutyryloxymethyl ester and succinic acid bis-(1-butyryloxy-ethyl)ester. These compounds are prepared as agents to deliver formaldehyde, and are aimed at different medical uses to the current compounds.
Prior art compounds include WO9747584, which describes a range of polyol succinates.

In the example given therein, Y is an H or alkyl group. Each succinate compound contains multiple succinate moieties linked by a group of structure C(Y)—C(Q), and each ester acid is therefore directly linked to a moiety containing at least two carbon atoms in the form of an ethyl group O—C—C. Each compound disclosed contains more than one succinate moiety, and the succinate moiety is not protected by a moiety of type O—C—X where X is a heteroatom.
Various succinate ester compounds are known in the art. Diethyl succinate, monomethyl succinate and dimethyl succinate are shown to be inactive in the assays exemplified below, and fall outside the scope of the invention.